If you have questions that are important in your survey, you can make them required so that respondents have to answer them. This needs to be done while you are creating the survey because once the survey is published you will not be able to go back and edit it.

When a question is required, a red asterisk will appear to the left of the question. The survey cannot be submited unless all of the required questions are answered.

To make a question required:

1. While adding/editing questions in step one of creating the survey, you will have to check the box next to "The respondent is required to answer this question".
2. Make sure to click Save once you are finished.

Note: Once the survey is published, you will be limited in the types of edits you can make. You will not be able to edit whether a question is required once the survey has been published.